abstract: Microbial electrochemical cells (MxCs) are a novel technology that use anode-respiring bacteria (ARB) to bioremediate wastewaters and respire an electrical current, which can then be used directly to produce value-added products like hydrogen peroxide (H2O2). Ninety-five percent of the world’s H2O2 is currently produced using the anthraquinone process, whose production requires expensive and potentially carcinogenic catalysts and high amounts of electricity. However, the amount of H2O2 that can be produced from these microbial peroxide-producing cells (MPPCs) has not been thoroughly investigated. Predicting potential H2O2 production in MxCs is further complicated by a lack of mathematical models to predict performance utilizing complex waste streams like primary sludge (PS). A reactor design methodology was developed for MPPCs to systematically optimize H2O2 production with minimal energy consumption. H2O2 stability was evaluated with different catholytes, membranes, and catalysts materials, and the findings used to design and operate long-term a dual-chamber, flat-plate MPPC using different catholytes, ferrochelating stabilizers, and hydraulic retention times (HRT). Up to 3.1 ± 0.37 g H2O2 L-1 was produced at a 4-h HRT in an MPPC with as little as 1.13 W-h g-1 H2O2 power input using NaCl catholytes. Attempts to improve H2O2 production by using weak acid buffers as catholytes or ferrochelating stabilizers failed for different reasons. A non-steady-state mathematical model, MYAnode, was developed combinging existing wastewater treatment, anode biofilm, and chemical speciation models to predict MxC performance utilizing complex substrates. The model simulated the large-scale trends observed when operating an MPPC with PS substrate. At HRTs ≥ 12-d, the model demonstrated up to 20% Coulombic recovery. At these conditions, ARB required additional alkalinity production by ≥ 100 mgVSS/L of acetoclastic methanogens to prevent pH inhibition when little influent alkalinity is available. At lower HRTs, methanogens are unable to produce the alkalinity required to prevent ARB inhibition due to washout and rapid acidification of the system during fermentation. At ≥ 100 mgVSS/L of methanogens, increasing the diffusion layer thickness from 500 to 1000 μm improved Coulombic efficiency by 13.9%, while increasing particulate COD hydrolysis rates to 0.25/d only improved Coulombic efficiency by 3.9%. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2018

As lagoas facultativas mantêm uma biota característica, decorrente de sua área superficial, que permite grande disponibilidade de energia luminosa para a coluna de água e promove o estabelecimento da comunidade fitoplanctônica. A presença dos nutrientes na forma assimilável aos microorganismos autotróficos induz a síntese de biomassa, a qual provoca a supersaturação de oxigênio dissolvido, que se constitui como substrato necessário ao desenvolvimento de bactérias heterotróficas, responsáveis pela degradação aeróbia da matéria orgânica nas camadas superiores da lagoa. Este estudo teve como objetivo principal a caracterização da estrutura da comunidade fitoplanctônica em termo de diversidade de espécies, densidade abundância relativa e dominância na lagoa facultativa do módulo III da estação de tratamento de esgotos de mangabeira, na cidade de João Pessoa - PB. As amostragens foram realizadas em escala semanal e sazonal, com coletas entre 8 e 9 horas da manhã, no período de junho/2008 a fevereiro/2009, as regiões afluente e efluente. As alterações no comportamento sazonal das variáveis físicas, químicas e biológicas, assim como das climatológicas, foram analisadas através da ferramenta estatística multivariada da Análise de Componentes Principais (ACP). Foram identificados 36 taxa nas duas regiões de amostragem e apenas cianobactérias foram predominantes durante o período deste estudo. Contudo, não foi observada variação sazonal na composição da comunidade fitoplanctônica nas duas regiões de amostragem. Embora, algumas espécies foram mais frequentes na região afluente, a densidade total apresentou nítida variação sazonal, com valores entre 2,0 x \'10 POT.4\' e 1,2 x \'10 POT.5\' ind/mL. A cianobactéria Planktothrix agardhii, a qual pode produzir a hepatotoxina microcistina, foi a espécie que mais contribuiu para a densidade, assim como para o biovolume. / Facultative ponds keep a characteristic biota, as a result of its superficial area, wich permits high availability of solar energy to the water column favoring the establishment of the phytoplanktonik community. The presence of available nutrients to the autotrophic microorganisms leads to the synthesis of biomass cellular into the pond and it causes the oversaturation dissolved oxygen, which is necessary to the development of heterotrophic bacteria, responsible for aerobic stabilization of organic material at the upper layer of the pond. The main goal of this study was to caracterize the structure of phytoplanktonic community in relation to different species, biomass, relative abundance and dominance at the facultative pond of the module III of waste water plants of Mangabeira (João Pessoa - PB). Samples were taken in seasonal and weekly scale, with collects between 8 a.m to 9 a.m, in the period of June, 2008 to February, 2009, at the regions of inflow and outflow of effluents. Alterations in seasonal behavior of the physical, chemical and biological variables, as well as climatic, were analyzed through statistics multivariate tool of the principal component of analysis (PCA). It was identified 36 taxa on the facultative pond and only the cyanobacteria were predominant during the period of this study. However, it was not observed temporal variation in the composition of phytoplanktonic community at two collected regions. Although, it was noticed that some species were more frequent at the region of inflow than at the outflow. It was also observed that the high total phytoplanktonic density shows a clear seasonal variation, with values between 2.0 x \'10 POT.4\' and 1,2 x \'10 POT.5\' ind/mL. The cyanobacteria Planktothrix agardhii, which may produce hepatotoxic microcystins, was the species that more contributed for the density as well as the biovolume.

As indústrias químicas são consideradas como o segmento industrial que gera os efluentes mais perigosos ao meio ambiente. Em virtude das concentrações expressivas de poluentes, tanto orgânicos quanto inorgânicos, os efluentes dessas indústrias podem interferir na atividade da biomassa de estações de tratamento de efluentes (E.T.E.), diminuindo sua eficiência e gerando efluentes tratados, porém em desacordo com a legislação pertinente. Para prevenir tais efeitos, o recebimento de efluentes industriais em E.T.E.s pode ser precedido por pré-tratamento, dentre os quais, o biológico, otimizado pela adição de microrganismos com capacidade de degradar poluentes. Foram isolados microrganismos com capacidade de degradar os compostos identificados como responsáveis pela toxicidade do efluente final da E.T.E.: benzeno, clorofórmio, 1,2-dicloroetano, pentaclorofenol, tricloroeteno, tolueno e p-xileno. Foram realizados testes de bioaumentação para pré tratar o efluente industrial, que foram avaliados através de ensaios físico-químicos e de toxicidade aguda para Vibrio fischeri e Daphnia similis. Os resultados obtidos demonstraram que o pré tratamento reduziu a toxicidade do efluente final da estação de tratamento. / Chemical industries are considered the industrial sector that generates the most dangerous effluents to the environment. Due to the high pollutant concentration, either organics or inorganics, the chemical industries effluents may interferer in the biomass activity in wastewater treatment plants (WWTP), what may reduce its efficiency and generate treated effluents in disagreement to the concerned law. In order to prevent such effects, the industrial effluents disposal in WWTPs can be preceded by biological pretreatment, which can be optimized by adding microorganisms capable of pollutants degradation. Microorganism strains that are able to degrade the compounds identified as the responsible for toxicity levels in the WWTP final effluent: benzene, chloroform, 1,2-dichloroethane, pentachlorophenol, trichloroethene, tolune and p-xylene were isolated. Bioaugmentation tests aiming the chemical effluent pretreatment were performed and they were evaluated through physical-chemical analysis and acute toxicity tests for Vibrio fischeri and Daphnia similis. The results showed that the industrial effluent pretreatment reduced the toxicity levels in the WWTP final effluent.

In this study we compare the ability of nitrifying activated sludge (NAS) and nitrifying trickling filter (NTF) wastewater treatment to remove the following contaminants: acetaminophen, caffeine, 1,7-dimethylxanthine, cotinine, ibuprofen, sulfamethoxazole, triclosan, and trimethoprim. Removal of acetaminophen, cotinine and caffeine was greater than 99% and removal 1,7-dimethylxanthine, ibuprofen, and triclosan was greater than 90% using NAS and NTF treatment. Sulfamethoxazole and trimethoprim were inadequately removed in both NAS and NTF treatments. The horizontal, subsurface flow treatment wetland showed removals of 45-89% for sulfamethoxazole and greater than 96% for trimethoprim. There was no statistical difference (P>0.05) between aeration, temperature and vegetation in the treatment wetland for the removal of sulfamethoxazole and trimethoprim.

Wastewater treatment plants (WWTP) involve several complex physical, biological and chemical processes. Often these processes exhibit non-linear behavior that is difficult to describe by classical mathematical models. Safer operation and control of a WWTP can be achieved by developing a modeling tool for predicting the plant performance. In the last decade, many studies were realized in wastewater treatment based on intelligent methods which are related to modeling WWTP. These studies are about predictions of WWTP parameters, process control of WWTP, estimating WWTP output parameters characteristics. In many studies, neural network models were used to model chemical and physical attributes in the flow rate. In this Thesis, a data-driven approach for analyzing water quality is introduced. Improvements in the data collection of information system allow collection of large volumes of data. Although improvements in data collection systems have given researchers sufficient information about various systems, they must be used in conjunction with novel data-mining algorithms to build models and recognize patterns in large data sets. Since the mid 1990's, data mining has been successfully used for model extraction and describing various phenomena of interest.

The primary objective of this research is to model and optimize wastewater treatment process in a wastewater treatment plant (WWTP). As the treatment process is complex, its operations pose challenges. Traditional physics-based and mathematical- models have limitations in predicting the behavior of the wastewater process and optimization of its operations. Automated control and information technology enables continuous collection of data. The collected data contains process information allowing to predict and optimize the process. Although the data offered by the WWTP is plentiful, it has not been fully used to extract meaningful information to improve performance of the plant. A data-driven approach is promising in identifying useful patterns and models using algorithms versed in statistics and computational intelligence. Successful data-mining applications have been reported in business, manufacturing, science, and engineering. The focus of this research is to model and optimize the wastewater treatment process and ultimately improve efficiency of WWTPs. To maintain the effluent quality, the influent flow rate, the influent pollutants including the total suspended solids (TSS) and CBOD, are predicted in short-term and long-term to provide information to efficiently operate the treatment process. To reduce energy consumption and improve energy efficiency, the process of biogas production, activated sludge process and pumping station are modeled and optimized with evolutionary computation algorithms. Modeling and optimization of wastewater treatment processes faces three major challenges. The first one is related to the data. As wastewater treatment includes physical, chemical, and biological processes, and instruments collecting large volumes of data. Many variables in the dataset are strongly coupled. The data is noisy, uncertain, and incomplete. Therefore, several preprocessing algorithms should be used to preprocess the data, reduce its dimensionality, and determine import variables. The second challenge is in the temporal nature of the process. Different data-mining algorithms are used to obtain accurate models. The last challenge is the optimization of the process models. As the models are usually highly nonlinear and dynamic, novel evolutionary computational algorithms are used. This research addresses these three challenges. The major contribution of this research is in modeling and optimizing the wastewater treatment process with a data-driven approach. The process model built is then optimized with evolutionary computational algorithms to find the optimal solutions for improving process efficiency and reducing energy consumption.

Dairy processing waste (DPW) can cause many environmental problems if not treated well. Various wastewater treatment technologies have been applied to reduce the organics and inorganics in DPW. The overall objective of this research was to develop cost effective anaerobic digestion technology for hydrogen and methane production from DPW. This search included three phases of studies. In phase 1, we investigated continuous fermentations of algae, lawn grass clippings and DPW, commingled and digested in duplicate 60 L and 3,800 L Induced Bed Reactor (IBR) anaerobic digesters at mesophilic conditions in trials that went for about two years. The goal was to commingle municipal waste in such a way that no pH control chemicals would be required. The research also yielded information about solids loading rate (SLR), efficiency of chemical oxygen demand (COD) and solids removal and biogas production. Under the conditions of the study, commingling algae or grass with DPW made it possible to avoid the addition of pH control chemicals. In phase 2, we investigated the effects of pH, temperature, and hydraulic retention time (HRT) and organic loading rate (OLR) on hydrogen production from DPW in semicontinuous 60 L pilot IBR. Results show pH played a key role on hydrogen production and the optimal pH range was 4.8-5.5. Digestion under thermophilic temperatures (60 °C) had advantages of gaining higher hydrogen yield and suppressing the growth of methanogens. The optimal OLR was 32.9 g-COD/l-d at HRT of 3 days. Under optimal conditions, highest hydrogen yield was 160.7 ml/g-COD removed with 44.6% COD removal. In phase 3, a mathematic model was built and implemented in R based on Anaerobic Digestion Model No. 1 (ADM1) for predicting and describing the anaerobic hydrogen production process. The modified ADM1 was then validated by comparing the predictions with observations of anaerobic hydrogen production from dairy processing waste. The model successfully predicted hydrogen production, hydrogen content, methane content, VFA concentration, and digestion system stability. This study provides a useful mathematical model to investigate anaerobic hydrogen production process and stability.

Approximately 25% of households in the U.S. treat their wastewater onsite using conventional onsite wastewater treatment systems (OWTS). These systems typically include a septic tank or a series of septic tanks followed by a soil absorption system. They effectively remove biochemical oxygen demand (BOD), total suspended solids (TSS), fats and grease but are not designed to remove significant amounts of nitrogen. High nitrogen loading to coastal and ground waters can be dangerous to aquatic life and public health. Hence, there is a need for advanced onsite wastewater treatment systems that can effectively remove nitrogen. Making enhanced nitrogen removal for OWTS as our primary goal, a laboratory scale Hybrid Adsorption and Biological Treatment Systems (HABiTS) was developed and upon observation of its effective nitrogen removal capacity, a pilot demonstration study with two side-by-side HABiTS, one with recirculation and one without recirculation (only forward flow) were constructed and tested at the Northwest Regional Water Reclamation Facility in Hillsborough County (Florida). HABiTS employ biological nitrogen removal and ion exchange for effective nitrogen removal. HABiTS is a two-stage process which uses nitrification for the oxidation of ammonium to nitrate and ion exchange for ammonium adsorption that helps buffer transient loading and also acts as a biofilm carrier in its stage 1 biofilter and it uses tire-sulfur hybrid adsorption denitrification (T-SHAD) in its stage 2 biofilter. These sulfur pellets help promote sulfur oxidation denitrification (SOD) and tire chips are used for nitrate adsorption during transient loading conditions, as biofilm carriers for denitrifying bacteria, and can also be used as organic carbon source to promote heterotrophic denitrification because they leach organic carbon. For this research, HABiTS without recirculation is considered as the control system and the performance of HABiTS with recirculation was tested for its ability to further enhance nitrogen removal from HABiTS. Nitrified effluent recirculation is a common strategy employed in wastewater treatment for enhanced nitrogen removal. It is the reintroduction of semi-treated wastewater to pass through an anoxic pre-treatment chamber to achieve better quality effluent. Recirculation is said to improve and consistently remove nitrogen at any hydraulic loading rate and/or nitrogen concentration. This is because of the dilution of high BOD septic tank effluent with nitrified effluent which lowers COD:TKN ratio and also improves mass transfer of substrates in the stage 1 biofilter. Recirculation also provides some pre-denitrification in the pre-treatment chamber, thereby reducing nitrogen load on the system. The HABiTS with recirculation (R) was run at 1:1 ratio of nitrified effluent recirculation rate to the influent flow rate for 50 days, and at 3:1 ratio for the remaining period of this research (200 days). The forward flow system (FF) was run under constant conditions throughout the research and comparisons between the two systems were made for different water quality parameters (pH, DO, conductivity, alkalinity, TSS, chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP) and various nitrogen species). The final effluent ammonium results showed that the system with recirculation removed consistently > 80% NH4+-N during 1:1 and 3:1 recirculation ratios whereas the forward flow system achieved 57% removal. Further, an average of 81% total inorganic nitrogen (TIN) removal from the system influent was seen in the recirculation system’s final effluent when compared to an average of 55% in forward flow system’s final effluent. This research explains in detail, the impact of nitrified effluent recirculation on enhanced nitrogen removal in onsite systems and the results presented in this thesis proved that nitrified effluent recirculation provides promising enhanced nitrogen removal in an onsite wastewater treatment system.

Water and sanitation (WatSan) development projects impact both natural systems and societal structures where they are placed. A complex process of development, including inter-governmental policies, aid agencies, personal relationships, and community politics enhance and constrain the efficacy of these projects. This study presents the many ways in which the WatSan development process has unintended and unexpected returns for certain community groups. Using a political ecology framework, I look at power structures, perceived and projected environmental impacts, multiple stakeholders, and individual discourses to critique how the right to water and sanitation is implemented in a specific community context. This project advances anthropological thought by showing a praxis-based study that links theory, on-the-ground, ethnographic experience, policy recommendations, and theoretical injections which relate to a variety of audiences, both within and outside of the academy. The project is conducted in two main field locations--La Paz and Sapecho, Bolivia. I employ a mixed-method approach, including interviews with development professionals and community members, a survey of water and sanitation users, focus groups with particularly impacted groups (e.g. water committees, students, and women), and various mapping techniques (GPS mapping, community-led) to address the space and place within which this project was realized. I give specific focus to sewage collection and wastewater treatment, two elements of the WatSan system that are distinctive in this rural developing-country context. WatSan development is not just infrastructure placement. It is a full process, a relationship. It comprises individual conversations, days of work, salaries, payment schedules, labor, expertise, and ongoing management practices. Individual perceptions of infrastructure efficacy, personal benefit, and best practices (both culturally and technologically) impact the long-term effectiveness of a project. Major tensions arise post-implementation: between community and aid agency, conservation and use, labor and upkeep, and sanitation and potable water. There are multiple influences and positions subsumed in this process. The study's political ecology approach, combined with foci on human rights, critical development, and water and culture, provides critical insights into the relationship between social and resource-based (water infrastructure) change. It looks at the ways in which the benefits and risks of a WatSan system are stratified, gendered, and power-laden. It further looks at the potential positive and negative outcomes of the system--all with an enviro-social focus. I look at how social and ecological relationships are tethered together (mutually constituted), how they are influenced by several levels of governance and policy. The experience of Sapecho shows how changes to WatSan environments can provide new water and sanitation access but in some cases, further engrain and exacerbate social inequalities. Provision of fresh water, sewage collection, and wastewater treatment infrastructure is not value-free--but it is necessary. This work tries to answer one small part of the question of how the right to water and sanitation can be best implemented in real-world situations.

Bioelectrochemical systems couple the oxidation of an electron donor at the anode with the reduction of an electron acceptor at the cathode, using microorganisms to catalyse one or both reactions. When the overall reaction is exergonic, a power output is generated and the system is referred to as microbial fuel cell (MFC); when power is added to the system and hydrogen is produced at the cathode through electrolysis of water, the system is referred to as microbial electrolysis cell (MEC). This PhD thesis is principally focused on the microbial fuel cells technology. Microbial fuel cells are regarded as a sustainable technology for electric energy generation from the oxidation of organic substrates contained in wastewater. The rising need for renewable energy sources and sanitation has encouraged intense research in this novel technology. Nevertheless, up untill now the interest has been primarily focused on the anodic oxidation of organic matter contained in wastewater. However, in addition to organics, wastewater also contains other pollutants, such as soluble nitrogen compounds, for which specific treatment is required. In conventional wastewater treatment systems, the organics available in the wastewater are typically used as electron donor during denitrification. However, a considerable fraction (>50%) of the chemical oxygen demand (COD) is still oxidized aerobically due to the large recirculation flows from the nitrification to the denitrification stages required in anoxic/aerobic configurations to allow for low nitrate levels in the final effluent. This increased COD demand is normally fulfilled by supplementary COD addition, with consequent increase of treatment costs. Alternatively, microorganisms can use inorganic carbon substrates and inorganic electron donors such as hydrogen for denitrification. However, the use of compressed hydrogen is hampered by its low solubility. As a solution, electrochemical hydrogen production permits in situ delivery of the electron donor and is advantaged by simplified control and dissolution of H2. The energy requirements to provide reducing power for denitrification can be decreased if bacteria use the electrode directly as electron donor without intermediate hydrogen production in bioelectrochemical systems. However, fundamental knowledge on bioelectrochemical denitrification is still lacking, therefore, this PhD thesis aims to fill some of these knowledge gaps and to solve some of the bottlenecks of the use of biocathodes. In particular, the goals of this work are: (i) to produce a suitable microbial community able to use the cathode as the sole electron donor during denitrification; (ii) to engineer a bioelectrochemical system able to couple the cathodic denitrification with the oxidation of organics at the anode; (iii) to characterize and quantify the electron losses during anodic and cathodic processes; (iv) to develop a bioelectrochemical system that maximises the nitrogen removal by integrating the nitrification stage into the cathode; finally, (v) to provide an insight into the structural properties of the biofilm performing nitrogen removal at the cathode. The results reveal that microbes can effectively utilize the electrode as electron donor for nitrate reduction to gaseous nitrogen at a redox potential that excludes intermediate production of hydrogen. Measurements revealed that acetoclastic methanogenesis and bacterial growth were responsible for causing the major electron losses at the anode. Adjusting the anodic potential did not achieve a significant overall reduction of the electron losses. At the cathode, the charge transfer efficiencies were instead very high, with the losses only due to the generation of nitrous oxide. Moreover, adjustments of the cathode potential resulted in higher efficiency. High carbon and nitrogen removal was obtained with a COD demand for denitrification as low as 2.4 g per g nitrogen denitrified, which is much lower than typically observed in heterotrophic–based nitrogen removal technologies (>7 g g 1). Nitrogen was removed at rates up to 0.256 kg N m-3 d-1, which is comparable to other autotrophic denitrification processes. Simultaneous nitrification and denitrification was observed in a combined system with cathodic aeration, at bulk dissolved oxygen (DO) levels up to 5 mg L-1, which is considerably higher than normally considered feasible for the process. Confocal laser scanning microscope analysis revealed the existence of a structured biofilm where putative nitrifying organisms occupied the outer layers in contact with the aerated bulk liquid, and putative denitrifying organisms occupy the layers closer to the electrode. These findings are significant in the field of bioelectrochemical systems as they help to unravel some of the complex questions relating to biocathodes. Additionally, the system provides an attractive option to achieve a very high level of nitrogen removal from wastewater with low COD/N ratios due to the selective utilisation of the COD for the denitrification reaction via the electrical transfer of reducing equivalents from the anode to the cathode. However, this research creates new questions, particularly regarding the mechanisms of electron transfer at the cathode. Also a number of practical design and optimisation challenges need to be overcome before wider applications can be considered.